During a Security Audit from your Windows Server you might have discovered that it is still supporting a Diffie-Hellman primes smaller than 1024-bit which is weak (see https://weakdh.org/) and you wish to change that.

To solve that there are two options possible:

1.) You could disable Diffie-Hellman completely via:

1a.) Run Regedit on the affected server

1b.) navigate to the following Registry location: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SChannel\KeyExchangeAlgorithms

1c.) Create a new sub key named Diffie-Hellman (if it didn´t already exists)